The trial also noted that the nutrient status of women receiving a supplement containing various essential nutrients increased significantly, whereas the control group developed vitamin B6 deficiencies during the late stages of pregnancy.
“Preconception/pregnancy supplementation in amounts available in over-the-counter supplements substantially reduces the prevalence of vitamin deficiency and depletion markers before and during pregnancy, with higher maternal plasma vitamin B12 maintained during the recommended lactational period," the report concluded.
Keith Godfrey, professor of epidemiology and human development at Southampton University and lead researcher on the study, explained that the findings were expected for the most part.
“We did anticipate finding widespread evidence of low or marginal vitamin status but were surprised at quite how high the prevalence was," he told NutraIngredients. "We speculate that the fall in cow’s milk intake, widespread eating of diets with a high level of ultra processed foods and reductions in meat intake are all likely to have contributed to the high prevalence."
Author and food standards, labelling and nutrition consultant TC Callis commented that the problem is definitely growing but is probably "more about the dire state of the UK diet than specifically the increase in plant-based diets".
"More than 60% of the calories consumed in this country derive from ultra-processed food; 'food' which is high in salt, sugar and highly processed carbohydrates and fats and low in actual nutrition—the kind of junk that used to be called ‘empty calories’," she said.
She added that although supplements can provide an effective solution to reducing such nutrient deficiencies, many available products for pregnancy are not providing nutrients in the correct amounts needed due to a lack of knowledge and outdated government guidelines.
“At the moment, a woman would need to take multiple products to ensure a sufficiency of the entire range of nutrients which have shortfalls in the UK,” she said.
Nutrition and pregnancy
It is well established that optimal nutrition is essential prior to and during pregnancy for the health outcomes of both mother and baby, with current guidelines recommending increased intakes of nutrients such as riboflavin, folate and vitamin A.
Research has demonstrated the benefits of supplementation with multiple micronutrients in women living in low-middle-income countries, however there is a lack of evidence of the benefits in high-income countries. Specifically, supplemented nutrients such as folic acid, vitamin D and B12 have been shown to reduce health risks in children later in life.
Despite this, human trials into the effects of micronutrient supplementation before pregnancy are lacking, which has hindered the development of accurate evidence-based guidelines for women.
Thus, the present trial sought to investigate the nutrient levels of women during early and late pregnancy, as well as six-months postpartum, in addition to examining the effect of maternal supplementation during pregnancy.
Study details
The randomised controlled trial recruited 1,729 women planning a pregnancy from three study sites in the UK, Singapore and New Zealand between 2015 and 2017. The women were randomly assigned to receive the intervention supplement or a standard vitamin supplement as control, from preconception to delivery.
Ingredients common to control and intervention formulations were folic acid 400 μg/day, iron 12 mg/day, calcium 150 mg/day, iodine 150 μg/day and β-carotene 720 μg/day. The intervention supplement also included riboflavin 1.8 mg/day, vitamin B6 2.6 mg/day, vitamin B12 5.2 μg/day, vitamin D 10 μg/day, zinc 10 mg/day, myo-inositol 4 g/day and probiotics (Lactobacillus rhamnosus and Bifidobacterium animalis sp. lactis).
Blood samples were collected prior to supplementation, one month into the intervention, in early and late pregnancy, and six months post delivery.
Findings indicated that the proportion of women at recruitment with marginal or low plasma status was 29.2% for folate, 7.5% and 82 for riboflavin, 9.1% for vitamin B12 and 48.7% for vitamin D. Furthermore, over 90% of all participants had low or marginal status for one or more of these vitamins at this stage.
Within the control group, levels of riboflavin, vitamin B6 and B12 declined throughout pregnancy, with 54.2% of participants developing low late-pregnancy levels of vitamin B6. However, supplementation for one month significantly increased associated nutrients in the intervention group, when compared to control.
Callis spoke to the potential risks associated with the observed B-vitamin deficiencies: “B vitamins support the development and function of the placenta. They reduce the risk of gestational diabetes, are essential in the formation and development of the brain and spinal cord, and the functioning of the central nervous system. They are also needed for RNA and DNA replication, red blood cell formation, iron metabolism and energy metabolism.”
She said that improved public education and serious changes to UK nutrition policies are critical to preventing these deficiencies and to reduce the development of health risks.
“The food supplements industry needs to wake up and make changes—because let's face it, the UK government is unlikely to do anything any time soon,” she added.
Source: PLOS Medicine
doi:doi.org/10.1371/journal.pmed.1004260
“Maternal B-vitamin and vitamin D status before, during, and after pregnancy and the influence of supplementation preconception and during pregnancy: Prespecified secondary analysis of the NiPPeR double-blind randomized controlled trial”
Authors: Keith M. Godfrey et al.